Wifi problem after ICS update

[mario386]

Hi,

I have this problem, that when I connect to the internet with my Xperia P throu wifi it will connect but after a minute it will not load pages anymore.

Everything works fine when connecting to the internet with DATA TRAFFIC.....what should i do?

Please help - everything was fine before with Gingerbread.

I updated to ICS yesterday on the 24th/aug.12.

Would it help if i repair the firmware? - and when repairing will all my previously installed Apps be deleted?

I'm from Estonia!

Best regards,

Thank you....
Mario

[iproute]

It is just a theory but here's why this may be causing your router to misbehave and create issues for other clients on the wireless network.

According to this paper - "But ...my station is awake! Power Save Denial of Service in 802.11 Networks" by Leandro F. Meiners

"The idea behind the attack, as mentioned above, is to trick the access point into

believing that the station under attack is in power save mode. Therefore, the access point will start buffering frames destined to the station, which results in a partial disconnection of the station from the network (the station can still transmit frames).

The beauty of this attack resides in the desynchronization that occurs between the station and the access point. Since the access point believes the station is in sleep mode it starts buffering inbound frames for it. Yet, the station, which isn't really in sleep mode, doesn't know the access point thinks it is in sleep mode and therefore, doesn't query the access point for its buffered frames."

When I did the network capture I noticed that the station (the phone) at around the 30 second mark starts sending Null Data frames with the power management bit set to 1 which tells the access point (or router) that it will go to sleep. The frames increase in frequence since that 30 second mark and quite possibly certain routers cannot handle it and it adversly affects the rest of the clients (laptops) connected to them.

[mickyb99]

That's certainly a good theory...it would seem to explain the crashes alright.

The bit I still can't understand though is why my phone works at my own house. Perhaps it's not sending the packet with the power management bit set...not sure why though. I'm pretty sure it's using 802.11n though because the router has that enabled plus the phone states that the wifi link speed is 65Mbps, which I think is only possible with 802.11n.

[iproute]

That is an excellent observation. I also don't have problems at home and my router is n capable. I cannot do a capture today but I'll try to do one tomorrow and compare to the previous trace.

More than likely the router is silently discarding those frames... Probably varies from router to router and between firmwares...

[iproute]

Did a capture while connected to my router at home and it was a very different trace. I don't think (still going through 7mb of data) the phone sent a single PWR MGT frame to the router telling it that it will go to sleep.

At the moment my theory is that since various routers and APs announce their capabilities in beacons, the phone never sends that frame to the ones that don't have the ability to "understand" it ... or that even if the phone does transmit that frame with that flag set they will ignore it ...not quite sure at the moment.

I was also able to reach out to one of the Sony Support moderators and he will relay the capture where the issue is evident to the Sony wireless experts for review.

[SamirSami]

I found where the Wi-Fi problem is, it’s with the WPA2 AES or WPA2 AES + TKIP, if you change it to something else say WEB or WPA “1” you will have no problems at all.

[iproute]

If that was the case and the phone had issues with AES it wouln't be able to even authenticate and associate to the AP. I am able to however and can browse for about a  minute or so...

Also no issues at home with WPA2...

Regardless...the standar's been out for years and releasing a firmware that requires you to change and lower your security posture is not a solution or something one would expect from a company such as Sony.

[mickyb99]

I also did a capture with a working router however my results differed to yours in that the phone did send PWR MGT frames. It sent about 9 PWR MGT frames within about 2 mins. The frames were both turning the PWR MGT on and off. The router also seemed to give an ack for these frames.

I'm not sure what that all that means though...maybe some routers are better able to handle the pwr mgt feature. I'll try a capture on the non-working router at the weekend to see if it matches the behaviour you saw. It's good to hear someone from sony will look into this issue though

BTW my working router is using WPA2 AES so I doubt that's the cause as SamirSami suggested...although it's great that it fixed it for him :smileygrin:

[iproute]

Looked at the wireshark capture again today and I filtered it on that frame type and flag and I can actually confirm your results - it does indeed send that frame when communicating with my home router. I guess since it wasn't nearly as frequent as it was with the AP I missed it initialy.

As I mentioned earlier my router also uses WPA2 and no issues at all...

Hopefully will hear soon from Sony whenever they review the capture on what is causing this...

[SamirSami]

I did noticed that it was not the security after all, I was changing lots of settings on every try, I was misled, the only thing that makes deference is the wireless mode, if set to “bg mixed” it will work, if set to “bgn mixed” it will not.

[tjv]

A slightly different problem wid me.... Tryin to access wifi in the office network,,, initially shows excellent signal strength, click connect... it says obtaining ip address for quite a long time and finally says bad signal... Only after the ics...